KDE devs have been quietly working on Plasma Keyboard, a new on-screen keyboard for desktop and mobile part of the “We Care About Your Input” KDE Goals initiative. Although not ready for texting yet, it has been making progress. Hopefully it’ll be in a screen near you soon. Join the effort!
https://invent.kde.org/plasma/plasma-keyboard
But it works.
Wanted to install OpenSUSE Tumbleweed with KDE as desktop on my Steam Deck without getting a keyboard. Had to use the Gnome Live image because it’s the only one with a working keyboard.